From 84623bef7b3266fdf5c143ccf762947c53c15025 Mon Sep 17 00:00:00 2001
From: Josh Gao <jmgao@google.com>
Date: Thu, 18 Mar 2021 17:16:08 -0700
Subject: [PATCH] Switch to Bionic's pidfd wrappers.

Bug: http://b/172518739
Test: treehugger
Change-Id: Ib6cac8f31ec64343c6eec6b82dac52888890c688
---
 lmkd.cpp | 16 ++++------------
 1 file changed, 4 insertions(+), 12 deletions(-)

diff --git a/lmkd.cpp b/lmkd.cpp
index 02a0ab6..2136ab0 100644
--- a/lmkd.cpp
+++ b/lmkd.cpp
@@ -30,6 +30,7 @@
 #include <sys/epoll.h>
 #include <sys/eventfd.h>
 #include <sys/mman.h>
+#include <sys/pidfd.h>
 #include <sys/resource.h>
 #include <sys/socket.h>
 #include <sys/syscall.h>
@@ -147,15 +148,6 @@
 
 #define LMKD_REINIT_PROP "lmkd.reinit"
 
-static inline int sys_pidfd_open(pid_t pid, unsigned int flags) {
-    return syscall(__NR_pidfd_open, pid, flags);
-}
-
-static inline int sys_pidfd_send_signal(int pidfd, int sig, siginfo_t *info,
-                                        unsigned int flags) {
-    return syscall(__NR_pidfd_send_signal, pidfd, sig, info, flags);
-}
-
 /* default to old in-kernel interface if no memory pressure events */
 static bool use_inkernel_interface = true;
 static bool has_inkernel_module;
@@ -1135,7 +1127,7 @@ static void cmd_procprio(LMKD_CTRL_PACKET packet, int field_count, struct ucred
         int pidfd = -1;
 
         if (pidfd_supported) {
-            pidfd = TEMP_FAILURE_RETRY(sys_pidfd_open(params.pid, 0));
+            pidfd = TEMP_FAILURE_RETRY(pidfd_open(params.pid, 0));
             if (pidfd < 0) {
                 ALOGE("pidfd_open for pid %d failed; errno=%d", params.pid, errno);
                 return;
@@ -2103,7 +2095,7 @@ static int kill_one_process(struct proc* procp, int min_oom_score, enum kill_rea
         r = kill(pid, SIGKILL);
     } else {
         start_wait_for_proc_kill(pidfd);
-        r = sys_pidfd_send_signal(pidfd, SIGKILL, NULL, 0);
+        r = pidfd_send_signal(pidfd, SIGKILL, NULL, 0);
     }
 
     TRACE_KILL_END();
@@ -3117,7 +3109,7 @@ static int init(void) {
     }
 
     /* check if kernel supports pidfd_open syscall */
-    pidfd = TEMP_FAILURE_RETRY(sys_pidfd_open(getpid(), 0));
+    pidfd = TEMP_FAILURE_RETRY(pidfd_open(getpid(), 0));
     if (pidfd < 0) {
         pidfd_supported = (errno != ENOSYS);
     } else {